Eilidh Geddes

Eilidh Geddes

PhD candidate in Economics

Northwestern University


I am a doctoral candidate in Economics at Northwestern University. My research focuses on health economics and industrial organization. I am on the 2022-2023 job market.


  • Health economics
  • Industrial organization
  • Applied Microeconomics


  • PhD in Economics, 2023 (Expected)

    Northwestern University

  • MA in Economics, 2020

    Northwestern University

  • BA/MA in Economics; BS in Mathematics, 2015

    University of Georgia

Working Papers

The Effects of Price Regulation in Markets with Strategic Entry: Evidence from Health Insurance Markets (Job Market Paper)

Regulators often enact price restrictions with the goal of improving access to affordable products. However, the design of these regulations may interact with firm strategic entry and exit decisions in ways that mitigate the effects of pricing regulation or eliminate access to certain products entirely. In the US individual health insurance market, the Affordable Care Act established community rating areas made up of groups of counties in which insurers must offer plans at uniform prices, but insurers do not have to enter all counties in a rating area. The exact design of each market has been left to individual states. Allowing partial entry creates trade-offs in rating area design. Larger areas may support more competition, but heterogeneous areas may promote partial entry as firms choose to not enter high cost areas. To evaluate these trade-offs, I develop a model of insurer entry and pricing decisions and investigate how insurers respond to rating area design. I find that banning partial entry increases overall entry, average prices, and consumer welfare. I quantify the trade-offs of increasing rating area size and find returns to size concentrated when marginal costs are similar across counties in a rating area. Regulators must balance promoting competition with pooling high and low cost consumers in rating area design.

The Expansionary and Contractionary Supply-Side Effects of Health Insurance

We examine how health insurance expansions affect the entry and location decisions of health care clinics. Exploiting county-level changes in insurance coverage following the Affordable Care Act and 1,721 retail clinic entries and exits, we find that local increases in insurance coverage do not lead to growth in the concentration of clinics on average using two-way fixed effects and instrumental variable designs. However, this null effect masks important heterogeneity by insurance type. Growth in private insurance leads to large growth in clinic entry, whereas clinic penetration is dampened by increases in Medicaid coverage. Consistent with a model in which firms face demand from both markets with administered and market-based pricing, we find that the positive (negative) supply-side effects of private insurance (Medicaid coverage) are concentrated in states with low provider reimbursements under Medicaid. We further show that similar location patterns are observed among other types of health care clinics, including urgent care centers. While it has long been accepted that reductions in the prices paid by consumers following insurance expansions should lead the supply side to expand to meet increased demand (Arrow 1963), our results demonstrate that whether health insurance expansions cause the supply side to expand or contract further depends on how the prices received by providers are affected.


STRT 444 Healthcare Economics

Teaching Assistant and Virtual Course Monitor: Fall 2020

ECON 349 Industrial Economics

Teaching Assistant: Fall 2021